Storage cells called “supercapacitors” or Electric Double Layer Capacitors (EDLC) consist of current collectors on which an active material comprising carbon materials is applied. This system is then immersed in a solvent containing a salt and is used to store electrical energy for subsequent use.
Carbon materials largely consist of coal. A novel technique has been developed in recent years, comprising the combination of coal with carbon nanotubes (CNT), optionally in combination with metal oxides (CN1388540). The document by Liu et al., Chinese Journal of Power Sources, Vol. 26, No. 1, 36, Feb. 2002 describes the capacitive properties of a composite carbon nanotube/activated carbon electrode. This document states that the CNT/carbon blends give rise to a higher capacitance and better self-discharge properties. There is no particular description of the electrode fabrication method.
However, no document describes a fabrication method, particularly industrially applicable, which addresses the problem of electrode aging and which is nevertheless one of the most crucial from the application standpoint, because the supercapacitor is presumed to have a certain service life.